高温合金焊接接头应力分析与疲劳寿命预测

Stress analysis and fatigue life estimation of four kinds of super-alloy welded joints

针对航空喷气发动机机匣上安装座的焊接结构,建立了对接焊、错位对接焊、不等厚对接焊、新材料对接焊等4种焊接结构的有限元分析模型,利用ANSYS软件进行了应力分析,得到了4种焊接接头的应力集中系数;用“成组对比实验方法”进行了上述4种焊接结构的应力疲劳试验验证,预测了它们的寿命区间.疲劳试件的扫描电镜(SEM)断口分析表明,应力集中区域的焊接缺陷是影响疲劳寿命最主要的因素.

In accordance with the welded structures on the mount-box of jet engine case, the finate element model（FEM） models of four kinds of welded joints including normal butt welding, dislocation butt welding, non-isopachous butt welding and new material butt welding are established. Stress analysis of these butt welding＇s is carried out by means of the finite element analysis software ANSYS, and the stress-concentration-coefficient of the four welded joints is obtained. The stress fatigue tests are implemented on the four kinds of butt welding pieces. The experimental results are analyzed and compared using the method of group comparison, and the fatigue life for the four kinds of butt welding is predicted. The result of the scanning electron microscope（SEM） fracture analysis indicated that the defection in the stress-concentrated area is the dominant factor to affect the fatigue life of the weld-joint.